ABSTRACT
Drought is often described as a creeping phenomena. An increase in demand can lead to drought conditions just as surely as a decrease in water supply. Just defining drought has been a major challenge in studying it as a hydrologic phenomena. There are many ways to quantitatively define and analyze the phenomena of drought: runs approach; Palmer Hydrological Drought Index; frequency analysis; and Markov chain. Drought has always been one of the primary concerns for water supply planning. A basic problem for water supply planning and management is estimating the amount of storage necessary to meet a given demand. Two methods for estimating reservoir storage are the mass curve and the sequent-peak method. This chapter has defined and analyzed drought using a variety of approaches. One of the most important impacts from drought is reduced water supply. Water supply managers must plan for this contingency and provide adequate water storage to carry the system through the drought period.
